Leonardo da Vinci sketched an aerial screw, a helical lifting device intended to rise through the air.
The drawing appears in the Codex Atlanticus and is usually dated to around 1489. It shows a large spiral surface made from reeds and linen, supported by a framework and operated by people turning a central platform. Leonardo reasoned that the spiral might screw into the air in a manner analogous to a screw moving through a solid material.
The aerial screw is often described as an early conceptual ancestor of the helicopter, but it was not a functioning helicopter. The design lacked a modern engine, and its proposed human-powered arrangement could not supply enough lift for practical flight.
It is also easy to confuse this design with Leonardo’s parachute or his ornithopter studies. The aerial screw is specifically identified by its large helical rotor-like surface, not by a canopy or flapping wings.